Rebamipide Does Not Protect Against Naproxen-Induced Gastric Damage: a Randomized Double-Blind Controlled Trial Thiago Gagliano-Jucá1*, Ronilson A

Gagliano-Jucá et al. BMC Gastroenterology (2016) 16:58 DOI 10.1186/s12876-016-0472-x

RESEARCH ARTICLE Open Access Rebamipide does not protect against naproxen-induced gastric damage: a randomized double-blind controlled trial Thiago Gagliano-Jucá1*, Ronilson A. Moreno2, Tiago Zaminelli3, Mauro Napolitano4, Antônio Frederico N. Magalhães5, Aloísio Carvalhaes6, Miriam S. Trevisan5,JohnL.Wallace7 and Gilberto De Nucci3,7,8

Abstract Background: Rebamipide is a gastroprotective agent with promising results against gastric damage induced by non-steroidal anti-inflammatory drugs. The present study evaluated if rebamipide protects against naproxen-induced gastric damage in healthy volunteers. Changes in gastric PGE2 tissue concentration were also evaluated. Methods: After a preliminary endoscopy to rule out previous gastric macroscopic damage, twenty-four healthy volunteers of both sexes were divided into 2 groups. One group received sodium naproxen 550 mg b.i.d. plus placebo for 7 days, while the other group received sodium naproxen 550 mg b.i.d. plus rebamipide 100 mg b.i.d. At the end of treatment, a new endoscopy was performed. Gastric macroscopic damage was evaluated by the Cryer score and by the modified Lanza score. The primary outcome measure of the trial was the macroscopic damage observed in each treatment group at the end of treatment. Biopsies were collected at both endoscopies for PGE2 quantification and histopathological analysis (secondary outcomes). Tissue PGE2 was quantified by ELISA. The randomization sequence was generated using 3 blocks of 8 subjects each. Volunteers and endoscopists were blind to whether they were receiving rebamipide or placebo. Results: All recruited volunteers completed the trial. Sodium naproxen induced gastric damage in both groups. At the end of the study, median Cryer score was 4 in both groups (Difference = 0; 95%CI = −1to0;p = 0.728). In the placebo group, the mean tissue PGE2 concentration was 1005 ± 129 pg/mL before treatment and 241 ± 41 pg/mL after treatment (p < 0.001). In the rebamipide group, the mean tissue PGE2 concentration was 999 ± 109 pg/mL before treatment, and 168 ± 13 pg/mL after treatment (p < 0.001). There was no difference in mean tissue PGE2 between the two groups (difference = 5; 95%CI from −334.870 to 345.650; p = 0.975). No significant change was observed at the histopathological evaluation, despite the evident macroscopic damage induced by naproxen. Conclusion: Rebamipide does not protect against naproxen-induced gastric damage in healthy volunteers. Trial registration: ClinicalTrials.gov, NCT02632812. Registered 14 December 2015. Keywords: NSAID, Histopathology, Human, ELISA, Endoscopy, Cryer score, Modified Lanza score

* Correspondence: [email protected] 1Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro (UFRJ), 21941-902 Rio de Janeiro, Brazil Full list of author information is available at the end of the article

© 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Gagliano-Jucá et al. BMC Gastroenterology (2016) 16:58 Page 2 of 7

Background After performing a preliminary gastroduodenal endos- Naproxen and other non-selective non-steroidal anti- copy at the Vera Cruz Hospital (Campinas, Brazil) to inflammatory drugs (NSAIDs) induce gastrointestinal rule-out prior macroscopic upper GI damage in the (GI) adverse events ranging from dyspepsia to upper and subjects, twenty-four healthy volunteers (12 men) were lower GI tract ulcers [1–3]. Naproxen 660 – 1000 mg enrolled in the study. Other exclusion criteria were: per day administered for 2 to 14 days is used as a model achlorhydria (pH > 6.5); positive fecal occult blood test; for NSAID-induced gastroduodenal damage in healthy drug abuse, including alcohol or tobacco. volunteers [4–8]. Rebamipide has been described as a GI mucosal pro- Treatment tector agent with promising results in prophylaxis and Volunteers were randomly divided into 2 groups: group treatment of GI ulcers caused by NSAIDs, H. pylori or A received 550 mg of sodium naproxen (Flanax® - Bayer) endoscopic submucosal dissection [9–15]. Results from plus an effervescent placebo (Biolab Indústria Farmacêu- animal studies have suggested that the protective effects tica Ltda.) diluted in 200 mL of water b.i.d. for 7 con- of rebamipide are attributable to stimulation of prosta- secutive days; group B received 550 mg of sodium glandin (PG) synthesis [16, 17]. In healthy volunteers, naproxen (Flanax® - Bayer) plus 100 mg of effervescent concomitant administration of rebamipide 100 mg with rebamipide (Biolab Indústria Farmacêutica Ltda.) diluted ibuprofen 600 mg t.i.d. for 7 consecutive days resulted in in 200 mL of water b.i.d. for 7 consecutive days. The a mean gastric damage score of 1.3 ± 1.0, which was randomization sequence was determined using the significantly lower than that of the control group (mean randomization generator available at www.randomiza- score of 2.9 ± 1.7), as assessed by the modified Lanza tion.com, using 3 blocks of 8 subjects each. Volunteers score (p = 0.032) [10]. In patients with rheumatic disease were blind to whether they were receiving rebamipide or rebamipide 100 mg b.i.d. also showed a protective effect placebo. To assure adherence, the drugs were adminis- against NSAID-induced gastric damage [18]. tered by a member of the research team (also blind to The present study evaluated whether rebamipide could treatment allocation) early in the morning and late in provide a protective effect against naproxen-induced the evening for the whole duration of the study. A gastric damage in healthy volunteers. pharmacist was responsible for labeling treatments as A or B, and for breaking the code at the end of the study. Methods Volunteers were required to be fasted in the morning Volunteers and were only allowed to eat at least 2 h after adminis- Volunteers of both sexes aged 18 years old or older tration of medications. In the evening, volunteers were without any significant cardiac, hepatic, renal, pulmon- required to be at least for 2 h without ingestion of food, ary, neurological, gastrointestinal or hematological dis- and were also asked to avoid eating for the following 2 h eases, as determined by their medical history, physical after the dose. examination, and routine laboratory tests (hematology, Adverse reactions were individually evaluated. Causal- blood biochemistry, urine analysis and fecal occult blood ity relationship to the treatment was assessed with the test), were invited to participate in this double-blind, aid of the Karch & Lasagna algorithm [19]. The necessity randomized, parallel placebo-controlled phase II single- of interruption of treatment or specific therapy was indi- center trial. All subjects tested negative for hepatitis B vidually assessed by the Principal Investigator depending and C (except for serologic scar), as well as HIV I and II, on the severity of the reaction and the causality relation- and were instructed to abstain from taking any medica- ship to the treatment. tion including over-the-counter medication for 2 weeks prior to and during the study period. Pregnancy was an Gastrointestinal damage evaluation exclusion criterion. All women enrolled had negative β- Gastroduodenal endoscopy was performed before the HCG. All volunteers were informed about the aim and start of the study and in the morning of the 8th day of risks of the study by the clinical investigator and they all treatment in all volunteers. Exams were performed by a signed a written informed consent statement before enter- single endoscopist. The primary outcome measure of the ing the study. The study was performed according to the trial was the macroscopic damage observed in each 2008 revised Declaration of Helsinki for bio-medical re- treatment group at the end of treatment. The number of search involving human subjects and the 1996 rules of mucosal erosions after treatment was counted and Good Clinical Practices. The study protocol was approved macroscopic mucosal injury scored according to Cryer by the Committee of Research Ethics of the University of [20] and to the modified Lanza score (MLS; Table 1) Sao Paulo, Sao Paulo, Brazil, on 26 November 2014 [9, 21]. Gastroduodenal ulcers were classified according (before the initiation of the study procedures), and the to the Sakita-Miwa classification. Additionally, a second study is registered at ClinicalTrials.gov, ID NCT02632812. endoscopist retrospectively evaluated the exams, blind to Gagliano-Jucá et al. BMC Gastroenterology (2016) 16:58 Page 3 of 7

Table 1 Cryer and modified Lanza scores according to Chemical Monoclonal Prostaglandin E2 EIA Kit (item gastroduodenal mucosal injury number 514010). Briefly, biopsies from the gastric an- Score Cryer score Modified Lanza score trum and corpus collected in both endoscopic proce- 0 Normal or erythema No hemorrhage or erosion dures were weighted and homogenized individually for observed 20 s by a Polytron in 1 mL of Na3PO4 buffer solution 1 Any amount of submucosal One or two hemorrhages or (pH = 7.4). Aliquots of 200 μL of the homogenate were hemorrhage or edema without erosions observed in one placed in a dry bath at 37 °C for 20 min and then centri- erosions. gastric area. fuged at 20,800 g for 30 s. Supernatant (150 μL) was col- 2 1 erosion ± submucosal Three to five hemorrhages or lected and diluted 1:100 (v/v) to be used in the ELISA. hemorrhage or edema. erosions observed in one gastric area. Each aliquot was assayed in duplicate and final PGE2 32–4 erosions ± submucosal Hemorrhages or erosions concentrations were adjusted for initial sample mass. hemorrhage or edema. observed in two gastric areas; Data are displayed as mean ± SEM. The person respon- six or more hemorrhages or sible for the quantification of PGE2 was blind to treat- erosions observed in one gastric area, with the total ment group allocation of volunteers. number not exceeding ten in the entire stomach. Histopathological evaluation 4 5 or more erosions and/or a Hemorrhages or erosions Biopsies from gastric antrum and corpus were immedi- single ulcer ± submucosal observed in three or more ately put in formaldehyde after collection. Samples were hemorrhage or edema. gastric areas; eleven or more hemorrhages or erosions stained in hematoxylin and eosin for characterization observed widely in the entire and graded according to a score described in Table 2. stomach. Giemsa stain was used to diagnose H. pylori infection. 5 Multiple ulcers ± submucosal Ulcer. The pathologist was also blind to treatments. hemorrhage or edema. Statistical analysis For evaluation of statistical difference of tissue PGE2 be- the scores given by the first endoscopist. If there was any tween treatments, a t-test was performed. A paired t test difference between the score given by the two endoscopists, was used to compare tissue PGE2 before and after treat- the final score would be the mean value of the two num- ments within each group. Endoscopic and histopatho- bers. Both endoscopists were blind to treatment group allo- logical scores between treatment groups were compared cation of volunteers. In each exam 3 biopsies were using the Mann–Whitney U-test. Gastrointestinal symp- collected from the gastric antrum and 3 from the gastric toms after treatments were compared by Fisher’s exact corpus for PGE2 quantification. Samples were immediately test. A p value <0.05 was considered significant. The washed in phosphate buffer saline at pH 7.4 and stored in- sample size planned for the study was 24 volunteers of − dividually in a dry Eppendorf tube and kept at 20 °C both sexes. This number was chosen based on the gas- until analysis. Another 2 biopsies from each stomach re- troprotective effects of rebamipide previously reported gion (4 total) were collected at each endoscopic proced- [9]. The calculation considered the Mann–Whitney U ure for histological analysis. Volunteers were questioned test analysis of the reported data on gastroduodenal about GI symptoms at every dose. Changes in gastric damage scoring by MLS. The effect size observed PGE2 concentration, histopathological characteristics (difference between treatments) was 67 % (median and GI symptoms at the end of the study compared to score after treatment of 3 and 1, in the placebo and baseline were evaluated as secondary outcome measures. rebamipide groups, respectively). Given a power of A more detailed questionnaire about GI symptoms such 80 % and a 0.05 chance of type 1 error, the original as heartburn, abdominal pain, fullness, nausea, vomiting, sample size estimation was 10 volunteers per group. blood in stools or others was completed before receiving The final number of 12 volunteers per group was the first dose and at the last day of treatment. In the chosen considering a 20 % rate of drop-out. Other questionnaires, when any symptom was reported, the vol- studies with rebamipide in healthy volunteers also unteer was asked to describe the intensity and frequency used similar sample sizes [10, 15]. of the symptom over the previous 7 days. Routine laboratory tests were repeated at the end of treatment, includ- Results ing fecal occult blood test. All 24 volunteers enrolled completed all procedures of the study. The median age of men was 24 years (range 18 – PGE2 quantification 49 years), mean weight was 75.7 kg (61.0 – 97.0 kg), mean Tissue PGE2 concentration was quantified by enzyme- height was 175 cm (152 – 186 cm), and mean body mass linked immunosorbent assay (ELISA) using Cayman index was 24.8 kg/m2 (20.2 – 28.7 kg/m2). Women had a Gagliano-Jucá et al. BMC Gastroenterology (2016) 16:58 Page 4 of 7

Table 2 Histhopathologic grade score developed for There was agreement between the endoscopists on the microscopic injury evaluation scores of all exams. Endoscopic findings and scores for each Score Findings volunteer using the macroscopic scoring systems are sum- 0 Normal gastric mucosa or mild chronic inflammation marized in Table 3. The median Cryer score was 4 in 1 Chronic gastritis without activity both placebo and rebamipide groups (Difference = 0; 95%CI = −1to0;p = 0.728). The median MLS was 4 2 Chronic gastritis with activity on antrum in the placebo group and 3.5 in the rebamipide group 3 Chronic gastritis with activity on the body (Difference = 0.5; 95%CI = −2to1;p =0.822). In the 4 Chronic gastritis with activity on antrum and on the body placebo group 2 volunteers (16 %) presented GI ulcers (1 ulcer each), while 4 volunteers (32 %) in the median age of 24.5 years (range 20 – 42 years), mean rebamipide group had ulcers (p = 0.320). Figure 1a weight was 69.5 kg (54.0 – 83.0 kg), mean height was and b illustrate the macroscopic aspect of the gastric 164 cm (153 – 170 cm), and mean body mass index was mucosa of volunteer 24 in the rebamipide group be- 25.9 kg/m2 (20.7 – 28.7 kg/m2). Three volunteers (two fore treatment and at the end of the study. men) were not allowed to enroll in the study because of The incidence of GI symptoms in each treatment gastric damage observation in the preliminary endoscopy. group is displayed in Table 4. Individual data regarding

Table 3 Summary of findings in the endoscopic procedure at the end of treatments Volunteer Treatment Scores before Cryer Lanza Antrum Duodenum Other # treatment Score Score 2 Placebo 0 3 2 4 erosions 5 Placebo 0 2 1 1 erosion + submucousal hemorrage 7 Placebo 0 4 4 >20 erosions 8 Placebo 0 4 5 2 erosions + 1 ulcer (Sakita A2) 10 Placebo 0 4 4 >10 erosions 12 Placebo 0 4 5 10 erosions + 1 ulcer (Sakita A2) 14 Placebo 0 4 2 5 erosions 16 Placebo 0 4 4 20 erosions 17 Placebo 0 4 4 10 erosions 3 erosions 18 Placebo 0 4 4 10 erosions 19 Placebo 0 4 4 10 erosions 23 Placebo 0 4 4 10 erosions 1 Rebamipide 0 4 4 20–25 erosions 3 Rebamipide 0 4 4 10 erosions 4 Rebamipide 0 4 5 10 erosions 1 ulcer (Sakita A2) 6 Rebamipide 0 3 1 2 erosions + erythema 9 Rebamipide 0 3 2 3 erosions 11 Rebamipide 0 3 3 2 erosions Submucousal hemorrhage in gastric fundus 13 Rebamipide 0 5 5 Small erosions + 2 ulcers (Sakita A2) 15 Rebamipide 0 4 2 5 erosions + erythema 20 Rebamipide 0 3 2 4 erosions 21 Rebamipide 0 4 5 Pylorus with edema and 1 ulcer (Sakita A2) 22 Rebamipide 0 3 2 3 erosions 24 Rebamipide 0 5 5 10 erosions + 4 ulcers (Sakita A2) Gagliano-Jucá et al. BMC Gastroenterology (2016) 16:58 Page 5 of 7

Table 4 Incidence of gastrointestinal symptoms Gastrointestinal Placebo (n = 12) Rebamipide (n = 12) P value symptom Before After Before After Before After Any 3 5 5 3 0.67 0.33 Abdominal pain 2 3 3 2 0.50 0.50 Heartburn 2 2 3 1 0.50 0.50 Nausea 1 2 1 1 0.76 0.50 Intestinal cramps 0 1 1 0 0.50 0.50 Fullness 1 0 0 0 0.50 1.00 Incidence of gastrointestinal symptoms in each treatment group before the beginning and at the end of the study. P value was calculated comparing incidence of symptoms between placebo and rebamipide groups before and after treatments by Fisher’s exact test

Histopathological evaluation At the initial endoscopic procedure, median histopathological scores were 1 in both groups (Difference = 0; 95%CI = −3to1;p = 0.582). At the end of the study, median histopathological scores were also 1 in both groups (Difference = 0; 95%CI = −1to1;p = 0.997). At the initial endoscopy, 5 volunteers in each group were H. pylori positive. At the end of treatments, 6 subjects in each group were H. pylori positive. The individual histopathological score for each patient as well as H. pylori status before and after treatment is available in Additional file 3: Table S3.

Discussion The present study did not find any evidence of a gastro- Fig. 1 Photographic documentation of the endoscopic procedure in a volunteer in the rebamipide group (a) before and (b) after treatment protective effect of rebamipide on naproxen-induced gastroduodenal damage as assessed by endoscopic macroscopic evaluation. This result differs from previous GI symptoms is available in Additional file 1: Table S1. findings, in which rebamipide treatment resulted in less There were no statistical differences between treatment severe gastric damage induced by NSAIDs [9, 10, 15]. groups at the end of the study. All fecal occult blood One possible explanation for the different results found tests were negative at the end of treatment. in the present work is that naproxen was more aggressive than others models of NSAID-induced gastric damage. To evaluate this possibility, previously published PGE2 quantification data was further analyzed. Treatment with indomethacin In the placebo group, the mean tissue PGE2 concentra- at 75 mg/day without rebamipide for 7 consecutive days tion was 1005 ± 129 pg/mL before treatment, and 241 ± resulted in a median MLS of 3. When treatment was as- 41 pg/mL after treatment (difference = 764; 95%CI from sociated with rebamipide 100 mg t.i.d., median MLS was 477 to 1051), which corresponded to a mean inhibition 1 [9]. Treatment with ibuprofen 1800 mg/day for 7 con- of PGE2 synthesis of 76.0 % (p < 0.001). In the rebami- secutive days without rebamipide resulted in a median pide group, the mean tissue PGE2 concentration was MLS of 3. When volunteers received rebamipide con- 999 ± 109 pg/mL before treatment, and 168 ± 13 pg/mL comitantly with ibuprofen, median MLS was 2 [10]. By after treatment (difference = 831.5; 95%CI from 612 to performing the Mann–Whitney U-test to compare MLS 1051), a mean inhibition of 83.2 % (p < 0.001). There scores from the placebo group in the present study to was no difference between the two groups in PGE2 those found in the placebo groups of the previously tissue concentration before treatments (difference = 5; mentioned studies, no difference in gastric lesion scores 95%CI from −334.870 to 345.650; p = 0.975). The indi- among these 3 models of NSAID-induced gastric dam- vidual PGE2 concentration found for each volunteer be- age was observed (indomethacin vs. naproxen, p = 0.475; fore and after treatment is available in Additional file 2: ibuprofen vs. naproxen, p = 0.343; indomethacin vs. ibu- Table S2. profen, p = 1.0). However, since the characteristics of Gagliano-Jucá et al. BMC Gastroenterology (2016) 16:58 Page 6 of 7

volunteers enrolled in the aforementioned studies are Additional files very different from those of the present study and trials designs are not the same, final conclusions cannot be Additional file 1: Table S1. Gastrointestinal symptoms occurrence in the previous 7 days as reported by each volunteer before the initiation drawn from these statistical analyses. and at the end of treatments. (DOCX 17 kb) Since all the aforementioned studies evaluated Japa- Additional file 2: Table S2. Individual PGE2 concentration found at nese or Korean subjects [9, 10, 13, 15, 18], population each assay for each gastric biopsy of each region evaluated, before and characteristics may have influenced the results. Higher after treatment, for each volunteer. (DOCX 19 kb) gastric pH is known to be a protective factor in NSAID- Additional file 3: Table S3. Individual histopathological scores and H. pylori induced gastric damage. The incidence of hypochlorhy- status before and after treatment for each volunteer. (DOCX 15 kb) dria in the Japanese population is higher than in western countries, affecting more than 40 % of individuals over Abbreviations ELISA, Enzyme-linked immunosorbent assay; GI, Gastrointestinal; MLS, Modi- 50 year olds in Japan [22], while in the Unites States the fies Lanza score; NSAIDs, Non-steroidal anti-inflammatory drugs; PG, incidence varies from 8 % in young adults to 11 % in the Prostaglandin. elderly [23, 24]. The higher gastric pH might facilitate the observation of the protective effect of rebamipide re- Acknowledgements Not applicable. ported in Asian individuals. Another possibility for differences in rebamipide effects in NSAID-induced gastric Funding damage is the genetic and dietary characteristics of the The study was funded by Biolab Indústria Farmacêutica Ltda. The funding populations evaluated in each study. body approved the study design and the methods that were used for data acquisition and analysis, but had no involvement with the interpretation of One difference of the present study is that the daily dose data or with the composition of the manuscript. of rebamipide was 200 mg, while most previous reports treated volunteers with 300 mg of rebamipide per day Availability of data and materials [9–15, 25, 26]. However, rebamipide at 200 mg/day in All the data supporting the findings of the study is contained within the manuscript and its supplementary files. patients with rheumatic disease showed a protective effect in NSAID-induced gastroduodenal mucosal injury [18]. It Authors’ contributions is unlikely that a reduction in 33 % of the dose would TGJ and GDN designed the research; TGJ, RAM, TZ, MN, AFNM, AC and MST abolish the supposed effect of rebamipide. A lower dosage performed the research; TGJ, RAM, TZ, MN, AFNM, AC, MST, JLW and GDN analyzed the data; TGJ, JLW and GDN wrote the paper. All authors read and of rebamipide was chosen due to safety concerns. Most of approved the final manuscript. the safety data about rebamipide comes from studies in Asian populations. This is the first time a study evaluated Authors’ information effects of rebamipide in a Brazilian population. Not applicable. Increased PG synthesis was previously suggested as a Competing interests possible mechanism for mucosal protection of rebami- The authors declare that they have no competing interests. pide [16, 17]. If so, rebamipide should not have a protective effect in NSAID-induced gastric damage through Consent for publication modulation of PG synthesis, since NSAIDs block the ac- Written consent to publish the identifiable information and the images of the volunteer’s endoscopic procedures, as well as the identifiable tivity of cyclooxygenases. information of the endoscopist that performed the exams were obtained. In the present study, no significant histopathological change of the gastric mucosa was seen at the end of Ethics approval and consent to participate treatment in neither groups, despite the clear aggressive- The study protocol was approved by the Committee of Research Ethics of the University of Sao Paulo, Sao Paulo, Brazil (approval number 809.508). All ness of naproxen observed on macroscopy. These results study subjects gave written informed consent before entering the study. confirm previous reports that identified the histological features characteristic of NSAID users only in a subset Author details 1Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de of patients, and that microscopic findings do not correl- Janeiro (UFRJ), 21941-902 Rio de Janeiro, Brazil. 2Galeno Research Unit, ate with macroscopical damage [27, 28]. This may reflect Campinas, Brazil; Faculty of Medical Sciences, Metropolitan University of 3 that the histological parameters used lack sufficient Santos, Santos, Brazil. Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil. sensitivity or else, the mechanism responsible for the 4Department of Pharmacology, ICB – University of Sao Paulo (USP), appearance of erosions and ulcers is independent of the 05508-900 Sao Paulo, Brazil. 5Department of Gastroenterology, Faculty of degree of inflammation. Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil. 6Brazilian Society for Digestive Endoscopy (SOBED), Sao Paulo, Brazil. 7Unicastelo Medical School, University Camilo Castelo Branco (UNICASTELO), Conclusion Fernandopolis, Brazil. 8Department of Pharmacology, ICB – University of Sao Rebamipide 200 mg/day does not protect against Paulo (USP), Sao Paulo, Brazil. naproxen-induced gastroduodenal damage in healthy Received: 26 November 2015 Accepted: 27 May 2016 volunteers. Gagliano-Jucá et al. BMC Gastroenterology (2016) 16:58 Page 7 of 7

References anti-inflammatory agents on the gastric and duodenal mucosa. Am J 1. Wolfe MM, Lichtenstein DR, Singh G. Gastrointestinal toxicity of nonsteroidal Gastroenterol. 1981;75(1):17–21. antiinflammatory drugs. N Engl J Med. 1999;340(24):1888–99. doi:10.1056/ 22. Morihara M, Aoyagi N, Kaniwa N, Kojima S, Ogata H. Assessment of gastric NEJM199906173402407. acidity of Japanese subjects over the last 15 years. Biol Pharm Bull. 2001; 2. Maiden L, Thjodleifsson B, Theodors A, Gonzalez J, Bjarnason I. A 24(3):313–5. quantitative analysis of NSAID-induced small bowel pathology by capsule 23. Dressman JB, Berardi RR, Dermentzoglou LC, Russell TL, Schmaltz SP, Barnett enteroscopy. Gastroenterology. 2005;128(5):1172–8. JL, et al. Upper gastrointestinal (GI) pH in young, healthy men and women. 3. Sostres C, Gargallo CJ, Arroyo MT, Lanas A. Adverse effects of non-steroidal Pharm Res. 1990;7(7):756–61. anti-inflammatory drugs (NSAIDs, aspirin and coxibs) on upper 24. Russell TL, Berardi RR, Barnett JL, Dermentzoglou LC, Jarvenpaa KM, gastrointestinal tract. Best Pract Res Clin Gastroenterol. 2010;24(2):121–32. Schmaltz SP, et al. Upper gastrointestinal pH in seventy-nine healthy, doi:10.1016/j.bpg.2009.11.005. elderly, North American men and women. Pharm Res. 1993;10(2):187–96. 4. Aadland E, Fausa O, Vatn M, Cohen H, Quinlan D. Protection by misoprostol 25. Talley NJ, Riff DS, Schwartz H, Marcuard SP. Double-blind placebo-controlled against naproxen-induced gastric mucosal damage. Am J Med. 1987;83(1A):37–40. multicentre studies of rebamipide, a gastroprotective drug, in the treatment 5. Aabakken L, Osnes M. Gastroduodenal lesions induced by naproxen. An of functional dyspepsia with or without Helicobacter pylori infection. endoscopic evaluation of regional differences and natural course. Scand J Aliment Pharmacol Ther. 2001;15(10):1603–11. Gastroenterol. 1990;25(12):1215–22. 26. Mizukami K, Murakami K, Hirashita Y, Hisamatsu A, Ogawa R, Uchida M, et al. 6. Oddsson E, Gudjonsson H, Thjodleifsson B. Comparison between ranitidine Efficacy of rebamipide for low-dose aspirin-related gastrointestinal and omeprazole for protection against gastroduodenal damage caused by symptoms. J Clin Biochem Nutr. 2012;51(3):216–20. doi:10.3164/jcbn.12-27. naproxen. Scand J Gastroenterol. 1992;27(12):1045–8. 27. El-Zimaity HM, Genta RM, Graham DY. Histological features do not define 7. Sarosiek J, Marcinkiewicz M, Parolisi S, Peura DA. Prostaglandin E2 content NSAID-induced gastritis. Hum Pathol. 1996;27(12):1348–54. in residual gastric juice reflects endoscopic damage to the gastric mucosa 28. Frezza M, Gorji N, Melato M. The histopathology of non-steroidal anti- after naproxen sodium administration. Am J Gastroenterol. 1996;91(5):873–8. inflammatory drug induced gastroduodenal damage: correlation with 8. Bianchi Porro G, Lazzaroni M, Petrillo M. Double-blind, double-dummy Helicobacter pylori, ulcers, and haemorrhagic events. J Clin Pathol. 2001; – endoscopic comparison of the mucosal protective effects of misoprostol 54(7):521 5. versus ranitidine on naproxen-induced mucosal injury to the stomach and duodenum in rheumatic patients. Am J Gastroenterol. 1997;92(4):663–7. 9. Naito Y, Yoshikawa T, Iinuma S, Yagi N, Matsuyama K, Boku Y, et al. Rebamipide protects against indomethacin-induced gastric mucosal injury in healthy volunteers in a double-blind, placebo-controlled study. Dig Dis Sci. 1998;43(9 Suppl):83S–9S. 10. Kim HK, Kim JI, Kim JK, Han JY, Park SH, Choi KY, et al. Preventive effects of rebamipide on NSAID-induced gastric mucosal injury and reduction of gastric mucosal blood flow in healthy volunteers. Dig Dis Sci. 2007;52(8): 1776–82. doi:10.1007/s10620-006-9367-y. 11. Terano A, Arakawa T, Sugiyama T, Suzuki H, Joh T, Yoshikawa T, et al. Rebamipide, a gastro-protective and anti-inflammatory drug, promotes gastric ulcer healing following eradication therapy for Helicobacter pylori in a Japanese population: a randomized, double-blind, placebo-controlled trial. J Gastroenterol. 2007;42(8):690–3. doi:10.1007/s00535-007-2076-2. 12. Kobayashi M, Takeuchi M, Hashimoto S, Mizuno K, Sato Y, Narisawa R, et al. Contributing factors to gastric ulcer healing after endoscopic submucosal dissection including the promoting effect of rebamipide. Dig Dis Sci. 2012; 57(1):119–26. doi:10.1007/s10620-011-1850-4. 13. Kim JH, Park SH, Cho CS, Lee ST, Yoo WH, Kim SK, et al. Preventive efficacy and safety of rebamipide in nonsteroidal anti-inflammatory drug-induced mucosal toxicity. Gut Liver. 2014;8(4):371–9. doi:10.5009/gnl.2014.8.4.371. 14. Kurokawa S, Katsuki S, Fujita T, Saitoh Y, Ohta H, Nishikawa K, et al. A randomized, double-blinded, placebo-controlled, multicenter trial, healing effect of rebamipide in patients with low-dose aspirin and/or non-steroidal anti-inflammatory drug induced small bowel injury. J Gastroenterol. 2014; 49(2):239–44. doi:10.1007/s00535-013-0805-2. 15. Tozawa K, Oshima T, Okugawa T, Ogawa T, Ohda Y, Tomita T, et al. A randomized, double-blind, placebo-controlled study of rebamipide for gastric mucosal injury taking aspirin with or without clopidogrel. Dig Dis Sci. 2014;59(8):1885–90. doi:10.1007/s10620-014-3108-4. 16. Kleine A, Kluge S, Peskar BM. Stimulation of prostaglandin biosynthesis mediates gastroprotective effect of rebamipide in rats. Dig Dis Sci. 1993; 38(8):1441–9. Submit your next manuscript to BioMed Central 17. Qi Z, Jie L, Haixia C, Xiaoying Z. Effect of rebamipide on quality of and we will help you at every step: peptic ulcer healing in rat. Dig Dis Sci. 2009;54(9):1876–83. doi:10.1007/ s10620-008-0577-3. • We accept pre-submission inquiries 18. Seo YI, Park SH, Min DJ, Kim WU, Min JK, Lee SH, et al. Effects of rebamipide • Our selector tool helps you to ﬁnd the most relevant journal against nonsteroidal anti-inflammatory drugs (NSAIDs)induced • gastroduodenal mucosal injury. J Korean Rheum Assoc. 2001;8(2):73–80. We provide round the clock customer support 19. Karch FE, Lasagna L. Toward the operational identification of adverse drug • Convenient online submission – reactions. Clin Pharmacol Ther. 1977;21(3):247 54. • Thorough peer review 20. Cryer B, Feldman M. Effects of very low dose daily, long-term aspirin • Inclusion in PubMed and all major indexing services therapy on gastric, duodenal, and rectal prostaglandin levels and on mucosal injury in healthy humans. Gastroenterology. 1999;117(1):17–25. • Maximum visibility for your research 21. Lanza FL, Royer Jr GL, Nelson RS, Chen TT, Seckman CE, Rack MF. A comparative endoscopic evaluation of the damaging effects of nonsteroidal Submit your manuscript at www.biomedcentral.com/submit